In depth metal composition

Stg Silver: 925 parts silver 75 parts copper.

Yellow gold: Pure gold mixed with equal parts pure silver and copper - Amounts vary by carat.

Red gold: Pure gold mixed with a pure silver and copper but a little more copper than silver - Amounts vary by carat.

9ct white gold: Approx 2.4% Palladium. No nickel.

9ct white dark alloy: Approx 16% Palladium. 4% Platinum. No Nickel or any other base metals.

14ct white gold: Approx 15% Palladium. 2% Platinum. No Nickel and hardly any other base metals.

18ct white gold: Approx 18% Palladium. 3% Platinum. No Nickel or any other base metals. 

Platinum: 95% Platinum. 5% Copper or Ruthenium .